REAPER themes are files that can alter the appearance of REAPER. Some aspects of the appearance of the interface can be radically altered, others can be slightly altered and others are fixed and themes are unable to change their appearance whatsoever. You can only use one theme at a time.

Most themes are in the format '.ReaperThemeZip'. Such a theme can be easily installed, tried out and then removed if you don't like it, with no further consequence.(If a theme comes packed with other files, ignore them for the time being and only install the .ReaperThemeZip.)

You may download new REAPER themes from the Stash, or from this forum, or from a themer's website.

REAPER themes broadly retain compatibility, so even very old themes will work fine with modern versions of the program though they may not always look great, perhaps in areas that did not exist when the theme was made! There's no harm in trying them out, and if they are packaged as .ReaperThemeZip files its just as easy.

Installing a theme

Download the .ReaperThemeZip file to your computer. Remember where you put it! Explore to that folder and find the file. Run REAPER. Now drag and drop the .ReaperThemeZip file onto the REAPER window and ...that's it! REAPER will copy the file to the correct location on your hard drive (which is all that is needed for installation) and switch to that theme.

Changing theme

You can change which of your installed themes you use by going to 'Options > Themes > ' and choosing a different theme.

Layouts

A theme may come with a number of variations for certain panels:

Transport : the panel containing the transport controls, time position etc...

Envelope Panel (EnvCP) : The panels on the left of the arrange area where you control envelope automation.

Master Mixer Panel : The mixer panel for the master track.

Mixer Panel (MCP) : The mixer panel for each track.

Master Track Control Panel : The panel on the left of the arrange area where you control the master track.

Track Control Panel (TCP) : The panel on the left of the arrange area where you control each track.

You can change which layout you use by going to 'Options > Layouts > ' and choosing between the variations the theme maker has provided for each panel. Alternatively, you can do this using the Layouts tab in the 'Screensets/Layouts' window (View > Screensets/Layouts).

You may change layouts on a per-track basis by selecting one or more tracks and using 'Options > Layout Per Track > ' or by right clicking on a track and using 'Set Track Layout'.

To uninstall a theme from your system, you simply need to delete the .ReaperThemeZip from the appropriate folder. Find this folder by selecting 'Options > Show REAPER resource path in explorer/finder...' and opening the 'ColorThemes' folder.(If you installed any non-.ReaperThemeZip files that came with a theme, removing or even just disabling them may be much more complicated. Hopefully the theme creator will have provided instructions on how to do that.)

Themer makers have access to all the same functionality that is used in the creation of REAPER's default theme. The degree to which they can change things, however, is governed by the depth to which REAPER's theming functionality provides access to each element's appearance:

Full control over appearance, size, position, and resizing behaviour. - Transport, Envelope Panel (EnvCP), Mixer Panels (MCP), Track Control Panels (TCP) use the powerful WALTER functionality. These are probably the bits you'll see in the theme screenshot

Some control over appearance, but not size or position - Arrange area, MIDI Editor, Tabs, Scrollbars etc. The themer may also have had to make compromises over elements that share colour definitions or images.

No control; OS drawn elements. REAPER makes extensive use of your OS's provided functionality for drawing dropdowns, tick boxes etc. The appearance of these elements is determined by your OS, their size and position is hard-coded into REAPER. The themer will have had to make compromises to make the themed areas 'fit' with these OS elements.

A theme cannot add new controls or functionality to REAPER. However, some themes may remove some controls or visual elements entirely, or on certain layouts.

Custom Colouring

When you custom colour a track, the appearance of that colour on track panels, mixer panels and track items may have been defined by the theme maker, who has (from V5 of REAPER onwards) full control over where, and how strongly, the custom colour is applied.

Tinting - In older themes, or themes that do not use the V5 custom colour theming functionality, the custom colour is applied by compositing the colour over the top. The location and strength of this 'tint' for media items, as a user preference for all themes that use it, is set in 'Options > preferences > Appearance > Peaks/Waveforms > Custom Colors'.

If you are currently using a theme that makes use of the V5 functionality, these preferences will be grayed out to indicate that the preferences you may have set will have no effect on this theme.